Java Programmer Crib 10: Lombok

Maven :

<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.18</version> </dependency> 

You can also (but it is not necessary to add a plugin for static compilers, if you need to analyze the code after compiling Lombok), see here

Gradle

 plugins { id 'net.ltgt.apt' version '0.10' } dependencies { compileOnly 'org.projectlombok:lombok:1.16.18' apt "org.projectlombok:lombok:1.16.18" } 

There are also plugins for Idea , Eclipse , etc. If you build Gradle or Maven, it will be collected without these plug-ins, but Idea / Eclipse will probably show errors when analyzing the code.

Name: @NonNull
Description: handling variables
which should not receive null
Lombok code:

 public Example(@NonNull P p) { super("Hello"); this.name = p.getName(); } 

Common Java code:

 public Example(@NonNull P p) { super("Hello"); if (p == null) { throw new NullPointerException("p"); } this.name = p.getName(); } 

Name: Getter /
Setter
Description: easy creation of getters and
setters
Lombok code:

 @Getter @Setter private int age = 10; 

Common Java code:

 private int age = 10; public int getAge() { return age; } public void setAge(int age) { this.age = age; } 

Name: @ToString
Description: definition of annotation before class,
to implement the standard toString method
Lombok code:

 @ToString(exclude="f") public class Example 

Common Java code:

 public class Example { @Override public String toString() { return ...; } 

Name: @EqualsAndHashCode
Description: Easy creation of Equals and HashCode methods.
Lombok code:

 @EqualsAndHashCode( exclude={"id1", "id2"}) public class Example { 

Common Java code:

 public class Example { ... @Override public boolean equals(Object o) { ... } @Override public int hashCode() { ... } 

Title:
@NoArgsConstructor,
@RequiredArgsConstructor,
@AllArgsConstructor
Description: creating an empty constructor,
constructor including all final fields
or constructor including all possible fields
Lombok code:

 @RequiredArgsConstructor( staticName = "of" ) @AllArgsConstructor( access = AccessLevel.PROTECTED ) public class E<T> { 

Common Java code:

 public class E<T> { private E(T description) { ... } public static <T>E<T> of( T description ) { return new E<T>(description); } 

Name: Data
Description: generation of all utility methods,
immediately replaces the @ToString, @EqualsAndHashCode,
Getter , Setter , @RequiredArgsConstructor
Lombok code:

 @Data public class Example { private final String name; private int age; } 

 public class Example { private final String name; private int age; public Example( String name ) { this.name = name; } public String getName() { return this.name; } void setAge(int age) { this.age = age; } public int getAge() { return this.age; } @Override public String toString() { return ...; } @Override public boolean equals( Object o ) { .... } @Override public int hashCode() { ... } 

Name: Value
Description: creating immutable classes,
analogue of Data, but for immutable classes
Lombok code:

 @Value public class Example { private final String name; private int age; } 

Common Java code:

 public class Example { private final String name; private final int age; public Example( String name, int age ) { this.name = name; this.age = age; } public String getName() { return this.name; } public int getAge() { return this.age; } @Override public String toString() { return ...; } @Override public boolean equals( Object o ) { .... } @Override public int hashCode() { ... } 

Name: Builder
Description: implementation of the bulder pattern,
Singular - used for objects in
single copy (add item
in collections, etc.)
Lombok code:

 @Builder public class Example { private String name; private int age; @Singular private Set<String> occupations; } 

Common Java code:

 public class Example { private String name; private int age; private Set<String> occupations; Example( String name, int age, Set<String> occupations ) { this.name = name; this.age = age; this.occupations = occupations; } public static ExampleBuilder builder() { return new ExampleBuilder(); } public static class ExampleBuilder { private String name; private int age; private ArrayList<> occupations; ExampleBuilder() { } public ExampleBuilder name( String name ) { this.name = name; return this; } public ExampleBuilder age( int age ) { this.age = age; return this; } public ExampleBuilder occupation( String occupation ) { if (this.occupations == null) { this.occupations = new ArrayList<String>(); } this.occupations.add(occupation); return this; } ... public Example build() { Set<String> occupations = ...; return new Example(name, age, occupations); } @java.lang.Override public String toString() { ... } } } 

Name: @SneakyThrows
Description: Wrapped Check Exceptions
Lombok code:

@SneakyThrows (
UnsupportedEncodingException.class)
public String utf8ToString (byte [] bytes) {
return new String (bytes, "UTF-8");
}

Lombok code:

 public String utf8ToString(byte[] bytes) { try { return new String(bytes, "UTF-8"); } catch (UnsupportedEncodingException e) { throw Lombok.sneakyThrow(e); } } 

Name: @Synchronized
Description: easy creation of synchronized blocks
Lombok code:

 private final Object readLock = new Object(); @Synchronized public static void hello() { ...; } @Synchronized public int answerToLife() { ... } @Synchronized("readLock") public void foo() { ... } 

Common Java code:

 private static final Object $LOCK = new Object[0]; private final Object $lock = new Object[0]; private final Object readLock = new Object(); public static void hello() { synchronized($LOCK) { ... } } public int answerToLife() { synchronized($lock) { ... } } public void foo() { synchronized(readLock) { ... } } 

Name: Log
Description: adding logging initiation,
also allows you to select the type of logger: @CommonsLog,
@JBossLog, Log , @ Log4j, @ Log4j2, @ Slf4j, @ XSlf4j
Lombok code:

 @Slf4j public class Example { public static void main(String... args) { log.error("error"); } 

Common Java code:

 public class Example { private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LogExampleOther.class); public static void main(String... args) { log.error("error"); } 

Val simple creation of the final
variable with type inference,
that is, the val of which
argued

 val map = new HashMap<Integer, String>(); for (val entry : map.entrySet()) { ... } 

 final HashMap<Integer, String> map = new HashMap<Integer, String>(); ... for (final Map.Entry<Integer, String> entry : map.entrySet()) { ... } 

Name: @Cleanup
Description: A simple definition of resources.
so that they automatically close
after the end of the code.
(not so relevant when using
try with resources)
Lombok code:

 @Cleanup InputStream in = new FileInputStream(args[0]); @Cleanup OutputStream out = new FileOutputStream(args[1]); ... 

Common Java code:

 InputStream in = new FileInputStream(args[0]); try { OutputStream out = new FileOutputStream(args[1]); try { ... } finally { if (out != null) { out.close(); } } } finally { if (in != null) { in.close(); } }